cyanotype speckling

Good morning all you cyanotypists,

This week I had a phenomenon happen with my 16 students that I have never
had happen in my cyanotype practice--the white speckling that sometimes
happens with cyanotype.

I figured it was a coating issue and they roughed up the paper fibers
(Platine). OR they didn't use enough solution. Those are the two
troubleshooting solutions I have written in my alt process manual.

But, whoops, I remembered that I had mixed my Tween to a 50% solution
instead of a 20% as recommended, and in a redo, one of my students no longer
got the speckles. Unfortunately I DIDN'T have "professor error" written as a
cause in my manual, so it can't possibly be that :).

However, I am not going to be so quick to assume this is the only issue,
even though I share it with you all for interest's sake.

I had not added a preservative to Solution A (did so yesterday, after
filtering the solution) and was musing if it is possible that when mold
starts growing in solution A, it might be so microscopic to cause these very
regular speckles?

Or even could FAC fall out of solution, or is it very soluble as I have
always assumed?

At the moment I am blaming it on the Tween, but I would appreciate any other
experiences with this phenomenon and what you all figured was the cause. No
stone left unturned.

Teaching a class is always a wonderful way to learn because in essence you
have 16 "testers". But when it comes to gum I am not going to make them
test tonal inversion....

The most exciting thing has been to teach them how to make their own curves
with the PDN system and watch those curves finally appear this week on the
computer screen. There is no better example to use than a side by side
print from an uncurved and a curved negative to show the value of learning a
system.

And, I've been having a blast printing that same print (uncurved and curved)
at 30 minutes dry time (usual), 5 hr, 30 hr, and a week to examine contrast
and speed of coated paper. It appears that there is a small loss of
contrast and speed with paper that sits a while, but not enough to make it
throwaway. My two cents. I'd appreciate other experiences here, too.
chris
Received on Sat Jan 28 10:36:10 2006